fix: maxValue of bin may large than max, making empty bins

Author: 666haiwen

packages/vdataset/__tests__/bin.test.ts

@@ -200,6 +200,13 @@ describe('bin transform', () => {
     expect(bins[9].x0).toBe(10);
     expect(bins[9].x1).toBe(11);
   });
+  test('bins in max value and threshold 2', () => {
+    const data = [1, 1, 1, 2, 5, 7, 8, 9, 10, 11, 12, 14].map(v => ({ v }));
+    const bins = bin(data, { field: 'v', bins: 10 });
+    expect(bins.length).toBe(7);
+    expect(bins[6].x0).toBe(13);
+    expect(bins[6].x1).toBe(15);
+  });
 
   test('bins in steps', () => {
     const data = [1, 1, 1, 2, 5, 7, 8, 9, 10].map(v => ({ v }));

packages/vdataset/src/transform/bin.ts

@@ -238,20 +238,30 @@ export const bin: Transform = (data: Array<object>, options?: IBinOptions) => {
     }
   } else {
     // fallback to bins count (default 10)
-    const bins = options.bins && options.bins > 0 ? Math.floor(options.bins) : 10;
+    let bins = options.bins && options.bins > 0 ? Math.floor(options.bins) : 10;
     // If the data range is larger than 1, prefer integer thresholds when possible.
     if (max - min > 1) {
       const start = Math.floor(min);
       const stepSizeInt = Math.ceil((max - start) / bins);
       thresholds = new Array(bins + 1);
       for (let i = 0; i <= bins; i++) {
         thresholds[i] = start + stepSizeInt * i;
+        if (thresholds[i] > max) {
+          bins = i + 1;
+          thresholds.length = bins;
+          break;
+        }
       }
     } else {
       const stepSize = (max - min) / bins;
       thresholds = new Array(bins + 1);
       for (let i = 0; i <= bins; i++) {
         thresholds[i] = min + stepSize * i;
+        if (thresholds[i] > max) {
+          bins = i + 1;
+          thresholds.length = bins;
+          break;
+        }
       }
     }
   }